When I installed mine it was noticeable. Quicker revs, definitely less parasitic loss of hp to the wheels. The before / after dyno comparison isn't a fair one since it was also comparing e54 to e90 that was the primary want of the pull.This is nice to know you have what I'm planning to do... I have a very curious question(s) 1). How does it feel after installing? 2). Any noticeable rev changes? 3). I have a theory that using that CF Drive Shaft will actually reduce the loss of power from crank to tires, by chance did you do a dyno afterwards to see if it freed up an ponies?